Aircraft



Jan. 5, 1943. E. F. ANDREWS AIRCRAFT Filed Feb. 12, 1958 2 She ets-Sheet 1' Jan. 5, 1943. E. F. ANDREWS AIRCRAFT Filed Feb. 12, 1958 2 Sheets-Sheet 2 Patented Jan. 5, 1943 STATES 'ATENT A oF'FicE Edward F. Andrews,. ihicago, Ill. Application February 12; 1938, Serial No. 190,171. 4 Claims. (euro-164) This invention relates to aircraft and has for its principal object to provide an improved aircraft.

A further object of the invention is to provide an improved propeller and means associated therewith whereby the propeller automatically moves into a low drag position when it is no longer driven.

A. further object of the present invention is the provision of a counterweighted propeller blade adapted to occupy a position generally perpendicular to the propeller shaft when the shaft is rotated, and which is automatically biased to to Fig. 2 showing a modified drive for the propeller;

Fig. 11 is a fragmentary view corresponding to the central portion of Fig. 6 illustrating the reduced width of the power pylon when the mechanism shown in Fig. 10 is employed;

Fig. 12 is a sectional plan view of the power pylon, the section being taken on the line l2-l2 of Fig. 1; I

13 is a cross-sectional detailed view of one of the auxiliary wings, the section being taken on 1 the line i3-l3 of Fig. 6; and

a position substantially parallel to said shaft when the rotation of said shaft ceases. I

It is a further object to provide a propeller blade having a counterweight which occupies a position generally p pendicular to the propeller shaft when the shaft is rotated, and which occupies a position substantially coaxial with said shaft with the counterweight partially surrounding and streamlining the shaft and its hub when the shaft rotates below a predetermined speed.

Fig. 14 is a plan view of one of the wings and one of the auxiliary wings, the upper enclosing portion of the wings being removed to show the enclosed supports, this view being seen as indicated by the arrows I l-ll on Fig. 6.

The drawings illustrate a power soarer, by

' which term it is intended to define an aircraft which is adapted to be raised by ordinary rising F air currents, and which is provided'with a motor of light weight whereby the aircraft may be sustained and transported from location to location Other objects, advantages, and capabilities of the invention will appear from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings in which,

Fig. 1 is a side elevation'of a power soarer empropeller;

Fig. .6 is a front elevational view of the power soarer on a reduced scale;

Fig. 7 is a fragmentary sectional view taken in the line 1 -7 of Fig. 1, showing the main landing wheels in the manner in which they are mounted and actuated;

- Fig. 8 is a. similar view showing "the wheels in stowed relation;

9 is a fragmentary perspective view showthe manner in which one .of the main wheels is'imounted; n

10 is a fragmentary sectional view similar the propelled 3d in order to take advantage of rising air currents for soaring. The invention is not, however, intended to be limited to such a device since it embodies many features and aspects which are applicable also to airplanes which must be power driven in order to fly for sustainedperiods. The

drawings illustrate, and the following description pertains not only to the improved propeller and the automatic movement thereof to a low drag position. when its drive is terminated, but also to a number of other features described and claimed in certain of my copending applications. Among these are a retractible alighting gear arrangement and the related feature of covering openings in the fuselage into which the land n gear is retracted, which are disclosed and claimed in my copending applications Serial Nos. 148,085, filed June 14, 1937, and 386,511, filed April 2, 1941; a retracting ground contacting meansadapted to prevent nosing over of the aircraft, the control of which is correlated to that of the landing gear and a propeller supporting and driving arrangement, which are disclosed and claimed in the latter of the two applications referred to, which, incidentally, is a division of the instant application.

meral 2B designates the fuselage of the aircraft. The front part of the fuselage may be enlarged, especially in the case of an airplane, to provide a chamber 2| forthe accommodation of two passengers who maysit side by side. The upper Referring to the drawings, the reference nu-' ing means 26.

portion 22 of the chamber 2| may be in the form of a transparent housing in order to provide visibility for the passengers in all directions. The fuselage is provided with elevators 23 and with a rudder 24, both of which may be actuated in the usual manner. The rudder 24 provides bearings for a small wheel 25 which projects below the rudder and the adjacent portion of the fuselage as shown in Fig. 1. The wheel 25 being mounted on the rudder 24, the machine may be steered on the ground by means of the rudder controls.

Adjacent the nose of the fuselage, the aircraft is provided with a skid or other ground contact- This skid is capable of being drawn up into a slot 21 which extends longitudinally in the under surface of the nose of the fuselage. When so retracted, the skid 28 fills up the slot 21 so as to complete the smooth outer form of the fuselage. The skid 26 is pivotally connected to the fuselage at 28 and is pivotally connected to the rod 29 of a dash pot 36, which is in turn pivotally mounted within the fuselage. A spring 36 within the dash pot 30 forces the rod 29 downward to the limit of its travel. The dash pct 30 strongly opposes sudden movements of the skid 26, while gradual movements of the skid from its position within its slot downwardly are permitted under the influence of the spring 30 and gradual upward movements from its operating position are permitted when suficient force is applied to overcome the spring 36 A cable 3| has one end connected to the, skid 26.

The other end of the cable is connected to a against the action of the spring 33 When, however, the crank 33 is actuated in the opposite direction, the cable 3| will be unwound from the drum and the action of the spring 36 will cause it to move downwardly. It will likewise be understood that when the skid 28 comes into forcible contact with the ground in landing, the dash pct 30 prevents therapid upward movement of the skid 26 so that the skid 26 takes the impact which is in part communicated to the fuselage and in part dissipated as heat in the dash pct 30. The spring 30 tends to maintain the skid 26 fully extended. A very effective braking action can be had by operatingthe elevator 23 so as to raise the tail and force the skid 26 firmly against the ground. The location of the skid 26 nearf" he nose of the fuselage effectively prevents the'iaircraft from nosing over despite the relatively rearward position of the additional members of the alighting gear.

The aircraft is also provided with two main supporting wheels 31, 31 which are pivotally mounted on stub axles 38. The stub axles 38 are carried by yokes 39 which are pivotally mounted .by means of bushings 40 and 4| on suitable lon-' gitudinal frame members 42 of the fuselage frame. The frame members 42 may suitably be located at the lower corners of the fuselage as shown in Figs. 7 and 8. The lower wall of the housing. is provided with openings 44 throughwhich the wheels 31 and the yokes 39 are adapted to pass into the interior of the fuselage, that is, from the position shown in Fig. 7 to the position shown in Fig. 8. The yokes 39 carry closure plates 45 which are adapted to close the openings 44 when the wheels 31 are moved into the position shown in Fig. 8. When the wheels 31 are projected from that position into the position shown in Fig. 7 for the purpose of supporting the aircraft on the ground, the plates 45 serve as mud guards to prevent mud or water from being splashed over the fuselage. When the wheels are in operating position, that is, the position shown in Fig. 7, abutments 40 and 4|.

which are integral with the bushings 40 and 4| respectively, engage the resilient damping pads 16 composed, for example, of shock absorbing rubber, which may be suitably carried by abutments 16 carried by elements of the frame work of the fuselage, as shown in Fig. 9, so that components of the force applied to the wheelsby contact with the ground may displace the wheels upwardly from their position in Fig. 7 only a. limited amount, determined by the compression of the resilient damping pads 16. It will be understood that the pads I6 are shown by way of example only and that any suitable damping means may be substituted therefor. The wheels 31 are actuated in unison by means of a crossed chain 43 which extends around sprockets 46 which are integral with or are rigidly secured to the bushings 40 of the yokes 39. The chain 43 is operatively engaged by a sprocket wheel 41 which is rigidly carried by the shaft 33. It will thus be seen that when the skid 26 is released to move downwardly the wheels 31 are moved from their position shown in Fig. 8 to their position shown in Fig. 7 and that when the wheels 31 are again stowed within the fuselage, the skid 26 is drawn upwardly into the slot 21.

The aircraft isprovided with a wing 48 which is located atan elevated point relative to. the

fuselage 20, being preferably located above the of the uniting structures H which connect the auxiliary wings 52 to the wing 48. Each auxiliary wing 52 is preferably united to the main wing 48 at a distance not more than a semispan from-the fuselage. The main wing bar 49 is located adjacent and preferably somewhat behind the aerodynamic center. The auxiliary wings 52 slope inwardly towards low positions on the fuselage 20 and they also slope rearwardly slightly as shown in Fig. 1. The auxiliary win 52 as shown in Fig.13 includes a forward bar 53 and a rear bar 54. The bars 49 and 50 of the additional lift which augments the lift of the main wing 48. The bars 53 and 54 are connected by struts 54 which, as shown in Fig..,14, extend transversely and also diagonally with respect to the widthof the wing 32. i

- from the juncture.

Owing to the double triangular truss formed by the two wing bars 53 and 54 of the auxiliary wings and wing bars 49 and 58 of the main wings, the main wing 48 is braced very eflectively against torsion at the point of juncture with the auxiliary wings 52. From this point outwardly, the wing barjll slopes forward, joining the main wing bar 89, at a point a short distance outwardly Outwardlyfrom the juncture of the main and auxiliary wings, the center of mass of the wing is kept as far forward as reach ofthe passengers so that it may be actuated The socket 11 is integral with a pair of bearingspossible, and torsion is taken by the D section' formed by the main wing bar 49 and the stiff surface covering employed on the top and bottom surface of the wing forward of the bar. The area of the main wing 48 can also be reduced as a result of the effective lifting surface provided by the auxiliary wings 52. rIt is to be noted that. the wheels 3! are located somewhat in front of the center of gravity of the machlne when fully loaded so that with the wheels 31 projected, the wheel will remain in contact with the ground although it will carry only a very lightfload. Under these circumstances, the skid 28.wi1l substantially clear the ground. The position of the wheels 37 is, however, suficiently close to the center of gravity so that the elevator 23 will control the angle of the. aircraft withonly a small relative airflow over its surface.

The propeller pylon is indicated by the reference numeral 55. This pylon extends upwardly from the fuselage 29 through the rear portion of the wing d8, terminating thereabove in a stream line upper end as shown at 58. In'cross section, the pylon is of streamline form as shown in Fig. 12, terminating in a relatively thin rear edge 57 which is located adjacent to the rear edge of the wing 88. The pylon frame may consist of-one or two pairs of laterally spaced, substantially vertical truss members 58 and a substantially vertical rear edge member 88. These vertical members are connected together by diagonal members 6! to form a highly rigid truss, including the rear edge member, which will be highly resistant against any tendency of the top of .the pylon to be twisted or bent relative to the fuselage.

At their upp r ends the posts 58 and to carry a bearing structure 82 which may suitably be an aluminum casting provided with suitable strengthening ribs 83. The upper surface of the casting 82 forms part of the streamlined surface 56 referred to previously. The casting 82 is provided with .a rearward extension 88 which supports a bearing 85 located somewhat rearwardly of the edge 57. The casting 82 serves as a support for bearings 88 -and 81 which may suitably be located in alignment with the two forward posts 58 and the two rearward posts 58 respectively. The three bearings 85, 88, and 8? are in alignment as shown in Fig. 2 and they rotatively support a horizontal shaft 68. The bearing 88 is a thrust bearing and is adapted to take the forward thrust exerted by the propeller 89 which is carried by the shaft 88. Betweenthe two bearings 88 and 87, the shaft 88 rigidly carries a pulley 78 over which runs a plurality of V belts 1 l The belts H extend downwardly through the pylon structure and pass around a 'pulley 72 of a motor 13. This motor is located at a low position in the fuselage .as shown in Fig. 1. Since soaring, I provide a cable '54 which is connected 19 which receive a pin 80 which is rigidly carriedat the rear end of the shaft 68- in a direction at right angles to the shaft 88. The pin 88 may suitably be rigidly mounted in a bearing 8| carriedby the rear end of the shaft 68. The inner faces of the bearings I9 have a working engagement with the sides of the block, as shown in Fig. 2. A counter weight 82, which is integral with the sockets 11 and the bearings 19, is located on the other side of the bearings 19 from the socket 11 so that it serves as an effective counterweight for the single blade 69 of the propeller. The counterweight 82 may suitably be in the form of a cradle which diverges away from bearings 79 so that it may be located in close conformity to the reduced rear extension 64 of the casting 63. In other, words, the counterweight 82 is of generally conical form with one open side so as to-permit it to become disengaged from the conical portion 84 of the casting 83 when the propeller moves from its position in Fig. 2 to its position in Fig. 3. The block BI is provided with a slot 83 in which is located a spring 84. This spring bears against a portion of the block 8| and a portion of the socket 11, as shown in Fig. 3, so that this spring automati-i cally tends to move the propeller 69 into align-1, ment with the shaft 88, that is, into a horizontaif position. This position is shown infull lines ig Fig. 1 and it will be readily seen that when t eii propeller is not in rotation it is moved into thi' horizontal position, where it creates little dragf opposing the movement of the aircraft. Whieri however, the engine is put intooperation an the shaft 88 is caused to rotate, the count weight 82, being out of balance with respect 1 the shaft 88, moves outwardly in the radial rection against the action of the spring 84, th bringing the propeller 69 into operation. When the engine is stopped, the centrifugal effect alsd ceases and the spring 84 becomes effective bring the propeller into the position in which is shown in Fig. 2.

In the embodiment of the invention shown in Figs. 10 and 11, the shaft 88 is supported by t bearings 85and85, both provided in the casting.- 88. The bearing 85 is a thrust bearing. At its forward end, the shaft 68 carries a bevel gear 88 which is enmeshed with a bevel gear 81 car ried by a shaft 88. The shaft 88 is supported in 88 is connected by a universal joint 98 to a shaft 9i whichextends downwardly through the pylon.-

the motor must be adapted to be started during toa handle and to a suitable starting means on the engine. The handle 75 is located within 75 55 towards the motor 13, the crankshaft of which} is indicated by the reference numeral '92. The crankshaft 92 is connected through a frictiom clutch 98 and a universal joint 94 to the shaft? ill. The shaft 9| may extend obliquely as shown in 10 in order that the engine 13 may be properly located to-bring the center of gravity forward so thatit is forward of the center of lift of the wing system. The friction clutch 93 is arranged or-adjusted 'so that when it is'subjected to the highest torque nor,- mally produced by the engine at any point in its cycle when delivering its maximum power. This clutch is, however, adapted to slip when it no slippage, occurs-i comes subjected to excessive torque produced, for example, by the tendency of the engine system and the propeller system to act as fly wheels oscillating relative to each other. This eflect can be prevented from building up excessive periodic torque stresses by the slippage of the clutch under these excessive stresses, energy being abs-orbed and dissipated as heat within the clutch, and the oscillations being thus efiectively damped. I prefer to adjust the clutch so that it can take a torque substantially above any torque produced by the engine while, at the same time, insuring slippage of the clutch at a torque below the elastic limit of the parts by a reasonable safety factor. If it is desired to make the torque more uniform, the clutch should be arranged to slip closer to the lower torque limit above stated, while if it is desired to minimize the energy losses and the heating of the clutch, it should be arranged to slip closer to the higher torque limit. When V belts are employed, the slip-page between the belts and the pulleys should be arranged to perform the function of the slipping clutch. It is to be noted that in this embodiment of the invention, the upper part of the pylon 55 may be substantially smaller than it is when the propeller is driven by belt and pulley. This is due to the fact that very-large power can be transmitted through very small bevel gears by the use of high quality alloy gear steels for instance, molybdenum steel, which are preferred for the gears 80 and 81. The reduction in size resulting from jacent the edge 51. The wall 90 extends downwardly to a position above the bottom of the fuselage and then upwardly to the rearmost baflie 98. Between the two walls 95 and 99, I provide in the upper surface of the fuselage an opening I00. This opening may be closed by a forwardly directed scoop IOI which is biased towards closing position by a spring I02. When the scoopis open, as shown in Fig. 1, and the propeller 60 is operating, the slip stream of the propeller is projected in part against the scoop I06 and the air is caused to flowinto the scoop, thenceforwardly and up,wardly through the high pressure com;

' partment, and thence into the low pressure conipartment above the baffles 98 and between the wall 96 and the wall 99.

Adjacent the rear edge of the pylon, I provide two doors I03 which are pivotally mounted at I and are rigidly connected to arms I05 located within the low pressure compartment. The doors I07 which are connected to the arms I05. The cords I01 pass over sheaves I 08, extend forwardly and are connected to a cord I09 which is secured to an arm IIO rigidly carried by the scoop IOI. The cord I09 is connected to a lever III suitably located adjacent the pilots position. By suitable manipulation of the lever III, the scoop IOI' and doors I03 may be opened to any desired extent. When the engine is not operating, the lever Iii may be moved to its most rearward position,

I03, which are adapted to open outwardly are located in front of the propeller and preferably adjacent ,the rearwardly extending portion of the fuselage so that the portion of the propeller adjacent the tip passes closely behind the door openings and creates asuction which effectively aids in creating a strong flow of air through the engine fins. This air is admitted through the opening I00 under substantial pressure due both to the movement of the machine through the air and also to the additional velocity of the air ime to the slip stream of the propeller.

' .Thedoors-I 03 are biased to closed positionby a and the scoop I0! and doors I03 are then closed by the springs I02 and I06, thus elminating all cooling drag. It is to be noted that with this cooling system, the engine is effectively cooled by the large current of air induced by the pressure difierence between opposite sides of the propeller, which pressure difference exists whenever the propeller is turning rapidly, even when the aircraft is moving at relatively slow speed or is standing still upon the ground. Due to the utilization of both the reduced pressure in front of the propeller, as well as the increased pressure behind the propeller, a larger total pressure difference may be maintained across the cooling surfaces of the engine, and cooling greatly enhanced, particularly under conditions of climb,

take-ofi, and ground running. Also, the scoop Q09 and the doors I03 may be operated with a very small degree of opening at highspeed or when maximum cooling is not required so as to occasion the minimum cooling drag.

Although the invention has been described in connection with these specific details of preferred embodiments thereof, it must be understood that such details are not intended to be limitative of the invention except as set forth in the accompanying claims.

Having thus described my invention, I declare that what I claim is:

1. In a folding screw propeller, a rotatable propeller shaft, a hub and counterweight member pivotally mounted thereon, a blade carried by said hub member, said hub, counterweight and blade being unbalanced relative to the propeller shaft when the blade is parallel to said shaft whereby said elements are moved by centrifugal force to a position in which said blade is substantially perpendicular to the major axis of said shaft when said shaft is rotated, and means ineluding .means operating under the influence of the air stream for causing the blade to move to a streamlined position by causing the major axis of said blade to lie coaxial with the major axis of said shaft member when the'rotation of said shaft member is reduced to a low speed.

2. In a folding screw propeller, a projecting bearing support member, a rotatable propeller shaft extending through said member, a ,hub

and a counterweight member carrying a blade,

bearing means pivotally connecting said hub and counterweight member with said propeller shaft to permit said hub and counterweight member to lie in a position generally parallel to and in a position generally perpendicular to said propeller shaft, said counterweight member being adapted in its said parallel position to engage and conform with said projecting bearing support, said counterweight, hub and blade being unbalanced relative to the shaft in said parallel position, whereby centrifugal force resulting from rotation of the shaft causes the counterweight, hub and blade to move into said perpendicular position.

3. In a folding screw propeller, a rotatable propeller shaft, a bearing supporting member for spring I00 and are adapted to be opened by cords terwelght seats around the supporting member and the blade i; substantially parallel to the shaft, said counterweight, hub and blade being unbalanced relative to said shaft when the blade is parallel to the shaft, whereby the blade is swungby centrifugal force resulting from rota- 4. A propeller assembly including a shaft, a bearing supporting member of generally conical form, a hub member pivotally mounted on the shaft, a blade carried by the hub, a counterweight in opposition to said blade; said counterweight being movable with said hub and being of generally divergent form, said counterweight being recessed to receive-the conical supporting member in one position of the hub, and a spring biasing said hub towards said position, said counterweight and associated elements being unbalanced relative to said shaft in said position, whereby rotation of the shaft causes the counterweight to swing away from the bearing supporting tion of said shaft into a position generally per- -15" member.

pendicular to said shaft.

EDWARD F. ANDREWS. 

